package com.fy56.platform.logistics.utils;

import java.security.MessageDigest;

public class MD5Util {
	public MD5Util() {
	}

	private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	/**
	 * 转换字节数组为16进制字串
	 * 
	 * @param b
	 *            字节数组
	 * @return 16进制字串
	 */
	public static String byteArrayToString(byte[] b) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++) {
			resultSb.append(byteToHexString(b[i]));// 若使用本函数转换则可得到加密结果的16进制表示，即数字字母混合的形式
			// resultSb.append(byteToNumString(b[i]));//使用本函数则返回加密结果的10进制数字字串，即全数字形式
		}
		return resultSb.toString();
	}

	private static String byteToNumString(byte b) {

		int _b = b;
		if (_b < 0) {
			_b = 256 + _b;
		}
		return String.valueOf(_b);
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0) {
			n = 256 + n;
		}
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String getMD5Code(String origin) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			resultString = byteArrayToString(md.digest(resultString.getBytes()));
		} catch (Exception ex) {
		}
		return resultString;
	}

	/**
	 * 进行md5字符中的比较
	 * 
	 * @param md5a
	 *            String
	 * @param md5b
	 *            String
	 * @return boolean
	 */
	public static boolean compareMD5(String md5a, String md5b) {
		boolean flag = false;
		if (md5a == md5b) {
			return true;
		}
		try {
			MessageDigest alga = MessageDigest
					.getInstance("MD5");
			flag = alga.isEqual(md5a.getBytes(), md5b.getBytes());
		} catch (Exception ex) {
		}
		return flag;
	}

	public final static String MD5Encoder(String s, String charset) {
		try {
			byte[] btInput = s.getBytes(charset);
			MessageDigest mdInst = MessageDigest.getInstance("MD5");
			mdInst.update(btInput);
			byte[] md = mdInst.digest();
			StringBuffer sb = new StringBuffer();
			for (int i = 0; i < md.length; i++) {
				int val = ((int) md[i]) & 0xff;
				if (val < 16){
					sb.append("0");
				}
				sb.append(Integer.toHexString(val));
			}
			return sb.toString().toUpperCase();
		} catch (Exception e) {
			return null;
		}
	}
}
